Whey isolates are filtered more, which increases protein content and usually decreases lactose content.
Organic beef concentrate: 76% protein, 7/8% lactose
Concentrated bovine lecithin: 80% protein, less than 1% lactose (it undergoes additional filtering to remove the lactose)
Goat milk concentrate: 80% protein, 5% lactose
Bovine isolate: 90% protein, less than 1% lactose
Isolates cost more, so they only make sense for people with lactose intolerance.